you are calculating (e.g., radius elbow, mitered bend, reducer)? What is your airflow rate (CFM) and duct size ?
They calculate the pressure loss in inches of water gauge ("wg) or Pascals (Pa) for various round and rectangular fittings. duct fitting loss calculator
The volume of air (CFM or L/s) passing through the fitting. you are calculating (e
A duct fitting loss calculator is an essential HVAC tool used to determine the pressure drop (resistance) caused by fittings like elbows, tees, transitions, and takeoffs within a duct system. These tools help calculate the total static pressure a fan must overcome to deliver the necessary air volume. Key Functions of a Duct Fitting Calculator you are calculating (e.g.
The diameter (round) or height and width (rectangular) of the duct.